flush on paired board, villain overbets

[dersl]

Party Poker, $0.50/$1 NL Hold'em Cash Game, 4 Players
LeggoPoker.com - Hand History Converter

UTG: $73.55
BTN: $69.86 35/5/3/33, River AF 10
SB: $134.55
Hero (BB): $225.78

UTG posts $1
Pre-Flop: 8[img]/images/graemlins/diamond.gif[/img] Q[img]/images/graemlins/diamond.gif[/img] dealt to Hero (BB)
UTG checks, BTN calls $1, SB folds, Hero checks

Flop: ($3.50) Q[img]/images/graemlins/club.gif[/img] 6[img]/images/graemlins/spade.gif[/img] A[img]/images/graemlins/diamond.gif[/img] (3 Players)
Hero checks, UTG checks, BTN checks

Turn: ($3.50) 6[img]/images/graemlins/diamond.gif[/img] (3 Players)
<font color="red">Hero bets $2</font>, UTG folds, <font color="red">BTN raises to $6</font>, Hero calls $4

River: ($15.50) K[img]/images/graemlins/diamond.gif[/img] (2 Players)
Hero checks, <font color="red">BTN bets $62.86 and is All-In</font>, Hero..

Actually, my plan was to c/RAI him on the river. But now that he overbets the pot...whats my play? Also, do like the river c/r or do you play b/f or b/c?